Knowing or predicting multi-phase conditions for wet steam flowing in a steam-distributing network is important to the engineering, management, and economics of steamflood enhanced oil recovery (EOR). All steam EOR systems involve a steam distribution system. Most steams used in oil field steam operations are “saturated” or “wet steam”. More specifically, the steam can be classified as a two-phase flow including steam vapor and liquid water. The proportion of each phase at a point in the distributions system can be affected by frictional pressure loss, liquid holdup, and unequal phase mixtures exiting piping junctions. Phase splitting occurs when liquid water separates from the steam. The two phases have very different properties, including energy content. Defining the amount of each phase delivered to any point of consumption is important to the efficient and effective operation of oil recovery projects.
One way of determining the amount of each phase in two phase steam flow is to measure steam quality. Steam quality can be defined as the ratio of the vapor phase flow rate divided by the total flow rate (vapor plus water). Previously known methods of measuring steam quality include using a dielectric steam quality sensor (DSQS). A DSQS measures an electrical impedance of a two-phase steam flowing through a region between two conductors. Using measurements from the DSQS, a flow engineer can determine steam quality. By determining the steam quality in a given enhanced oil recovery system, the flow engineer can maximize the effectiveness of the steam introduced to an oil well.
The extent and nature of mixing of the two phases, or “flow regime” is critical to the function of impedance sensing devices. However, the flow regime of two-phase flows can be unpredictable and, thereby, produce inaccurate measurements. Uncontrolled flow regime is one factor that can lead to inaccurate results when using a DSQS. In some instances, liquid phase forms a direct electrical connection between electrodes and/or conductive films, on one or more of the electrical insulating components, producing inaccurate measurements.